Apparatus and method for attaching abrasive pads to a drive plate

ABSTRACT

For use in a concrete floor grinding, polishing or burnishing machines, a combination of a drive plate and abrading pads attached to the drive plate is described. The abrading pads include a planar substrate having one or more posts projecting from a first major surface and a resin layer impregnated with abrasive grit on its second major surface. The drive plate includes areas thereon for receiving the substrate and where the areas each include at least one elongate aperture through which the post extends and when the substrate is shifted laterally, the posts become releasably locked in place.

CROSS REFERENCE TO RELATED APPLICATIONS

None

BACKGROUND OF THE INVENTION

I. Field of the Invention

This invention relates generally to machines for grinding and/or polishing and/or burnishing concrete, stone and tile flooring and more particularly to grinding heads and resin abrading pads designed for tool-less attachment to the rotatable drive plate of such grinding/polishing machines.

II. Discussion of the Prior Art

It is known that concrete and stone or tile surfaces can be made more attractive by first abrading the hardened concrete, stone or tile flooring to yield a smooth, planar surface and then subsequently polishing or burnishing that surface with resin pads to provide a high gloss glaze to the surface. Machines for grinding and/or polishing concrete, stone or tile flooring generally comprise a wheeled frame having a handle extending upward whereby an operator may steer the machine. Mounted on the frame is a motor having a vertical shaft extending through the top surface of a shroud and the shaft is connected to a drive plate within the shroud. Adapted to be affixed to the drive plate is a plurality of diamond grinding heads or a plurality of polishing or burnishing pads depending upon the operation to be performed.

Grinding heads and polishing or burnishing pads are subject to wear and need to be frequently replaced. It is therefore advantageous to be able to couple the grinding heads or polishing pads, as the case may be, to the drive plate quickly and easily and without the use of tools. Furthermore, the attachment must be in a way that positively locks the heads or pads to the drive plate so that centrifugal and other forces encountered during use do not result in separation of the heads/pads from the spinning drive plate when the machine is operating.

Examples of prior art approaches for coupling grinding heads to a drive plate are found in U.S. Pat. Nos. 8,272,924 and 8,585,466 to Van Eijden et al. where drive pins and permanent magnets are used to “stick” the heads to the drive plate. The U.S. Published Application 2013/0090047 A1 to Bin teaches the use of Velcro® hook and loop material for releasably joining a polishing tip holder plate to the machine's drive plate. Neither of these prior art attachment modes is deemed to be totally reliable and may result in unwanted decoupling during use, especially where irregularities in the concrete slab and the angular velocity of the pads induce omnidirectional forces to the floor-engaging pads, adversely impacting their holding power. The use of several dowel pins and permanent magnets as in the Van Eijden patents makes removal and replacement of the grinding heads and polishing/burnishing pads needlessly complicated and time consuming.

A need therefore exists for an improved way of releasably securing grinding heads and/or polishing or burnishing pads to the drive plate of a floor surface prep machine of the type described that resists decoupling during use and which allows quick replacement without the need for tools. The present invention achieves these ends.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided an abrading pad for attachment to a drive plate of a concrete or stone floor finishing machine where the abrading pad includes a planar substrate having a predetermined shape and with first and second major surfaces. Projecting perpendicular to a first major surface of the substrate is at least one post having a flange at a free end. Affixed to the second major surface of the substrate is a resin layer impregnated with an abrasive.

To affix the abrading pad to a circular metal disk comprising the machine's drive plate, a plurality of pockets may be formed inwardly from a first major surface, the pockets being regularly circumferentially spaced proximate the peripheral edge of the drive plate. The inclusion of pockets in the drive plate may not always be necessary. Each of the pockets may include at least one elongate aperture that extends through the thickness dimension of the metal disk. The elongate aperture comprises a first segment of a first size at one end and transitioning into a second segment of a second size less than that of the first size at an opposed end of the elongate aperture. The first size of the first segment is larger than the size of the flange on the pad's at least one post, allowing insertion of the post with the flange through the first aperture segment. The cross-sectional dimensions of the post are approximately the same as the size of the second circular segment such that when the pad is moved laterally, an interference fit is created when the pad is translated relative to the drive plate to the point where the flange is made to underlie the elongate aperture's second segment.

DESCRIPTION OF THE DRAWINGS

The foregoing features, objects and advantages of the invention will become apparent to those skilled in the art from the following detailed description of a preferred embodiment, especially when considered in conjunction with the accompanying drawings in which:

FIG. 1 is a side elevation view of a polishing pad constructed in accordance with the present invention;

FIG. 2 is a perspective top view of the polishing pad of FIG. 1;

FIG. 3 is a bottom perspective view thereof;

FIG. 4 is a plan view of a machine drive plate designed to accommodate the polishing pad of FIGS. 1-3; and

FIG. 5 is an enlarged partial view of the drive plate of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

This description of the preferred embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description of this invention. In the description, relative terms such as “lower”, “upper”, “horizontal”, “vertical”, “above”, “below”, “up”, “down”, “top” and “bottom” as well as derivatives thereof (e.g., “horizontally”, “downwardly”, “upwardly”, etc.) should be construed to refer to the orientation as then described or as shown in the drawings under discussion. These relative terms are for convenience of description and do not require that the apparatus be constructed or operated in a particular orientation. Terms such as “connected”, “connecting”, “attached”, “attaching”, “join” and “joining” are used interchangeably and refer to one structure or surface being secured to another structure or surface or integrally fabricated in one piece, unless expressively described otherwise.

Keeping the above points in mind and referring to FIGS. 1-3 of the drawings, a preferred embodiment of a floor abrading pad is displayed. The pad is indicated generally by numeral 10 and is seen to comprise a planar substrate 12 of a rigid plastic with polyurethane being preferred. The substrate here is shown as having a generally polygonal shape with radiused intersecting sides as seen in the views of FIGS. 2 and 3. However, it is to be understood that this shape is somewhat arbitrary and other shapes can serve as well.

With reference to FIG. 1, the substrate 12 is seen to have an upper major surface 14 and a lower major surface 16. At least one post and preferably first and second posts 18 projects perpendicularly from the lower major surface 16 and formed on the free end of each is a flange as at 20 and 22.

Bonded to the upper major surface 14 by a suitable adhesive is a substrate comprising, for example a resin layer 24, which is preferably partitioned into plural segments by intersecting score lines plainly visible in the view of FIG. 2. Intermixed with the resin are synthetic diamonds of a desired grit size. Pads of the type described may be offered with differing grit sizes ranging from course to very fine.

Having described the constructional features of the floor abrading pads to be used with a floor polishing, burnishing and grinding machine, consideration will next be given to the construction of the drive plate and especially the mode of attachment of the above described abrading pads thereto.

Referring to FIG. 4, a ring portion of a drive plate for attachment to a concrete, stone or tile floor finishing machine is indicated generally by numeral 30 and comprises an annular metal plate member 32 that may have a plurality of pockets 34 of a size and shape to receive a pad 10 therein and that are evenly distributed adjacent the periphery of the annular plate 32. As an example, and without limitation, with the annular plate 32 may be made of aluminum and may be 9.53 mm in thickness, the depth of the pockets 34 that are machined into the surface of the plate may have a depth of 3.05 mm. Other embodiments of a suitable drive plate may be void of such pockets, allowing a thinner and lighter plate material to be used. For example, a thickness of 6.35 mm for an aluminum ring similar to FIG. 4 but void of the pockets 34 has proven workable. Also, materials other than aluminum, such as a hard, non-brittle plastic, may be used in fabricating the drive plate.

Located between each of the pockets 34 is an oval aperture 36 that extends through the thickness dimension of the annular plate 32 and these punched oval apertures 36 function to further reduce the weight of the machine.

It may also be observed from FIG. 4 that the pockets 34 generally comprise eight-sided polygons where the intersections between adjacent linear segments are radiused and thus somewhat match the shape of the substrate 16 of the polishing pads 10.

Located in each of the pockets 34 is an elongate aperture 38 for receiving each post on the pad 10. The aperture(s) extend through a thickness dimension of the annular plate 32. Each of the elongate apertures 38 comprises a first segment 40 of a first size and shape at one end of the elongate apertures 38, and a second segment 42 of a second size and shape that is less than the first size and shape of the segments 40 and where the two segments are contiguously joined. In FIG. 4, the first segment is circular in shape and of a diameter allowing the flange 20, 22 to fit through it.

FIG. 5 is a greatly enlarged partial view of the annular plate 32 and one of the pockets 34 containing the elongated apertures 38 that comprise the first circular segment 40 and the contiguously joined second circular segment 42. The dashed line 44 in FIG. 5 is indicative of the fact that the drive plate 32 is undercut on its back side.

The diameter of the circular segment 40 is only slightly greater than the diameter of the flange 20 on the post 18 of the abrading pad 10 while the diameter of the second circular segment 40 is approximately the same as the diameter of the post 18. Thus, to affix an abrading pad to the drive plate, one merely inserts the flange 20 through the first circular segment and then laterally translates the pad to move the posts 18 into the second circular segment 42, and with the flange residing in the undercut represented by the dashed line 44. Because of the friction fit maintained between the abrading pad's posts 18 and the walls defining the second circular segment 42, a predetermined force must be applied by hand to the pad to again shift it so that the flange 20 is again aligned with the first circular aperture 40, allowing removal of a pad once it has become worn.

Because of the way that the pads are oriented when affixed to the drive plate in the manner described, it is oriented close to the periphery of the annular plate, thereby providing a maximum angular velocity which is conducive to increased polishing efficiency. Moreover, the high angular velocity results in a centrifugal force on the abrasion pad that serves to hold the abrading pad's posts in the far end of the drive plate's elongated aperture.

This invention has been described herein in considerable detail in order to comply with the patent statutes and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use such specialized components as are required. However, it is to be understood that the invention can be carried out by specifically different equipment and devices, and be used with a variety of grinding/polishing pads. As an example, rather than utilizing posts of round cross-section, they can be of other cross-sectional shapes. Furthermore, the flanges need not be circular, but should correspond to the shape of the elongated aperture segments so as to be able to be inserted through them. Also, various modifications, both as to the equipment and operating procedures, can be accomplished without departing from the scope of the invention itself. 

What is claimed is:
 1. A method of attaching floor abrading pads to a drive plate of a floor finishing machine comprising the steps of: a) providing a circular plate having a plurality of regularly circumferentially spaced elongate aperture extending through a thickness dimension of the plate proximate a periphery thereof, the elongate aperture including a segment of a first shape and size at one end thereof and contiguous to a segment of a second shape and size, less than the first size, at an opposed end thereof; b) providing a plurality of floor polishing pads, each comprising a planar substrate having a predetermined shape and with at least one post projecting from a first major surface of the substrate, the at least one post having a flange at a free end thereof, the shape and size of the flange being less than said first segment's shape and size and greater than said second segment's shape and size, and the post being approximately equal in shape and cross-sectional size to that of the second segment's shape and size; and c) inserting the flange of the at least one post of the floor polishing pad through the segment of the elongate aperture of said first shape and size and laterally displacing the floor polishing pad such that the post fits through the elongated aperture's segment of the second shape and size and the flange underlies the segment of the second shape and size.
 2. In combination; a drive plate for a floor finishing machine; and at least one floor abrading pad; the drive plate comprising a circular disk with first and second major surfaces each including a plurality of regularly circumferentially spaced elongate aperture extending through a thickness dimension of the metal disk proximate the periphery of the drive plate, said elongate apertures each comprising a first segment of a first size at one end of the elongate aperture that is contiguously joined to a second segment of a second size that is less than the first size at an opposed end of the elongate aperture; and the at least one floor abrading pad comprising a planar substrate having a predetermined shape and with a post projecting from a first major surface of the substrate, the post having a flange at a free end thereof where the size of the flange is less than said first size of the first segment and greater than said second size of the second segment and where the cross-sectional size of the post is such as to create an interference fit with walls defining the second segment when the flange is inserted through the first segment and the abrading pad is laterally displaced such that the flange is made to underlie the second segment.
 3. The combination of claim 2 wherein the drive plate further includes recessed pockets in the first major surface, the pockets corresponding in shape to the predetermined shape of the planar substrate and in surrounding relation to the elongate apertures.
 4. The combination of claim 3 wherein the pockets are each eight-sided polygons with radiused intersections.
 5. The combination of claim 4 wherein the floor abrading pad's planar substrate comprises a six-sided polygon with radiused intersections.
 6. The combination of claim 5 and further including a resin layer incorporating diamond grit on a second major surface of the floor abrading pad's planar substrate.
 7. The combination of claim 6 wherein the resin layer is partitioned by intersecting score lines.
 8. The combination of claim 2 wherein the second major surface of the drive plate includes a recess in the second major surface thereof and surrounding the second segment of each of the elongate apertures, the recess being sized to receive the flange on the free end of the post on floor abrading pads therein.
 9. The combination of claim 3 wherein each of the plurality of pockets each includes a pair of said elongate apertures with a predetermined spacing therebetween and the floor abrading pad includes a pair of said posts, each with a flange on a free end thereof, said posts being spaced so as to be capable of insertion into the pair of elongate apertures of a given one of said pockets.
 10. The combination of claim 2 wherein the first and second segments are generally circular, the post has a circular cross-section and the flange is circular.
 11. A resin pad for attachment to a drive plate for a floor abrading machine comprising: a) a planar substrate having a predetermined shape, the substrate having first and second major surfaces; b) at least one post projecting perpendicular to the first major surface; c) a flange surrounding a free end of the post; and d) a resin layer impregnated with an abrasive material the resin layer being adhered to the second major surface of the substrate.
 12. The resin pad of claim 11 wherein the resin layer is partitioned into plural segments by intersecting score lines.
 13. The resin pad of claim 11 wherein the planar substrate is generally polygonal with radiused intersecting sides.
 14. The resin pad of claim 11 having at least two posts, each with a flange on a free end thereof, the posts projecting perpendicularly to the first major surface.
 15. The resin pad of claim 11 wherein the abrasive material comprises diamond grit. 